1. Field of the Invention
The present invention relates to a combustion apparatus wherein a fuel injection portion is located rearward of a gas passable solid (upstream of the solid as viewed in an air flow direction), and a thermal facility provided with the combustion apparatus.
2. Description of Related Art
In a conventional burner, a fuel injection portion is located so as to face a combustion chamber. As a result, combustion is conducted near the fuel injection portion of the burner, so that a temperature of the fuel injection portion is high. Particularly, in a regenerative combustion type burner, since the fuel injection portion is located frontward of a heat storage member (on a combustion chamber side), the fuel injection portion is at a very high temperature.
Further, as a special case, Japanese Utility Model Publication SHO 62-118925 discloses a radiant tube wherein a fuel injection nozzle is located rearward of a heat storage member such that a tip of the nozzle contacts the heat storage member.
However, the above-described conventional apparatuses have the following problems:
With the burner where the fuel injection portion faces the combustion chamber, since the fuel injection portion is at a high temperature, the life of the burner is shortened. If the fuel injection portion is made from heat proof material, cost will be increased and machining will be difficult. Further, since a complicated mechanism cannot be provided to a high temperature portion,. the burner structure will have various limitations. PA1 With the burner in which the fuel injection portion is located rearward of the heat storage member like Japanese Utility Model Publication SHO 62-118925, according to tests conducted, it was seen that no flame was formed due to insufficient mixture of fuel and air. If the fuel injection portion was spaced apart from the heat storage member in order to pre-mix fuel and air, when exhaust gas flows through the heat storage member to heat the heat storage member to a high temperature, the mixture of fuel and air self-ignited and burned within the heat storage member to melt the heat storage member. Therefore, the burner having the fuel injection portion rearward of the heat storage member could not be actually used. PA1 (A) The combustion apparatus, provided with at least one burner, includes a gas passable solid therein. A fuel injection nozzle is disposed rearward of the gas passable solid (on an upstream side of the gas passable solid as viewed in an air flow direction). A pre-mixture region for pre-mixing fuel and air for combustion is provided between a most downstream portion of the gas passable solid and the fuel injection nozzle. PA1 (B) In a case where the combustion apparatus is a heat storage type burner, an air supply passage for supplying air for combustion includes a main air supply passage and a pilot air supply passage independent of each other. The fuel injection nozzle is disposed within the pilot air supply passage. PA1 (C) In a case where the combustion apparatus is a heat storage type burner provided at each of opposite ends of a radiant tube, a structure similar to the structure (B) is taken. PA1 (D) A direct heating type heat facility such as an industrial furnace, a boiler, and a chemical reaction container provided with the apparatus having the structure (B). An indirect heating type heat facility such as an industrial furnace, a boiler, and a chemical reaction container provided with the apparatus having the structure (C).